Transformer bushing terminal and hinged cover therefor



Nov. 20-, 1951 J. J. ZIMSKY TRANSFORMER BUSHING TERMINAL AND'HINGED COVER THEREFOR Filed Oct. 7, 1947 INVENTOR JOHN J. ZIMSKY Tatented Nov. 20, 1951 UNITED STATES TRANSFORMER BUSHING TERMINAL AND HINGED COVER THEREFOR John J. Zimsky, Pittsburgh, Pa., assignor to Pennsylvania Transformer Company, Pittsburgh, Pa., a corporation of Pennsylvania Application October 7, 1947, Serial No. 778,435

(Class 174-139) Claims. 1

This invention relates to a terminal for electric conductors and, in particular, to a terminal for the insulating bushings of a transformer or the like, having an insulating cover removably fitted thereover.

Distribution transformers as usually manufactured heretofore have been provided with curvedshank insulator bushings for the high-voltage terminals, the shank of the bushing being disposed normal-to the wall of the transformer tank through which it extends and the exposed end sloping downwardly and outwardly from an enclosure or bushing pocket secured to the tank and projecting outwardly therefrom. These curved-shank bushings and the pockets used therewith are expensive and materially increase the overall cost of the transformer. Distribution transformers are used in such large numbers that even small items in the cost thereof have substantial importance commercially.

I have invented a novel bushing termina1 and cover therefor particularly suited for the highvoltage leads of distribution transformers, which avoid the necessity for the curved shank and pocket of the conventional construction, thereby reducing the cost of manufacture while providing equally secure anchorage for the leads and adequate protection of the terminal from the weather and contact by linemen working in the vicinity or birds alighting thereon. In a preferred embodiment, the terminal of my invention comprises a block adapted to be secured against the end of an insulator bushing by a bolt extending thereinto. The block has an exposed outer face sloping outwardly and downwardly, and a stud projecting from said surface normal thereto having a hole adapted to receive the end of a conductor. A hood-like cover of insulating material open at the bottom and one end is movably mounted on the block and normally encloses said face, stud and the conductor end secured thereby. The cover is hinged to a bail pivotally mounted on the block so it may be swung up and tilted backwardly to expose the block thereby facilitating connection or disconnection of the high-voltage lead.

A complete understanding of the invention may be obtained from the following detailed description and explanation which refer to the accompanying drawings illustrating a present pre ferred embodiment. In the drawings,

Figure 1 is a central vertical section through a transformer bushing having the invention applied thereto;

Figure 2 is a side elevation of the terminal;

PATENT OFFICE Figure 3 is a bottom plan view thereof;

Figure 4 is an end elevation;

Figure 5 is a side elevation of the cover;

Figure 6 is an end elevation thereof;

Figure 7 is a bottom plan view;

Figure 8 is a transverse section therethrough taken along the plane of line VIHVTII of Figure 5; and

Figure 9 is a horizontal section taken along the plane of line IX-IX of Figure 5.

Referring in detail to the drawings, a transformer bushing ill has a terminal I l at the outer end thereof adapted to receive and anchor the end of a conductor l2 connected to a supply circuit. The terminal I! comprises a block 53 having a rearward bearing face M from which a boss is projects. The boss it extends into the void through the bushing and is secured thereto by a bolt i6 threaded into a tapped hole ii in the boss. One end id of a transformer winding is sweated into a hole in the head of the bolt 16. This bolt head bears on a shoulder is in the bushing. A bearing washer 2B is disposed between the bolt head and the shoulder. A sealing gasket 21 is disposed between the bearing portion 14 of the block l3 and the end of the bushing.

The block I3 has a downwardly and outwardly sloping face 22. A stud 23 extends upwardly and outwardly from this surface and is normal thereto. The stud has a hole '2 therethrough adapted to receive the end of the conductor ii. A clamp 25 slidable on the stud is adapted to engage the conductor end and hold it firmly against the face 2'2. A nut 26 is threaded on the stud for forcing the clamp against the conductor.

A cover 21 of insulating material is movably disposed over the terminal block 53 and conductor end 12. The cover is open at the end adjacent the end of the bushing and has a slot 28 in the bottom adapted to admit the conductor end i2. The cover is shaped generally like a hood, having sides 28, a top 38, a closed outer end 3] and a flange 32 around the other end which is open.

The block 13 has a transverse slot 33 formed in the top thereof. A wire ball 34 is seated in this slot and extends downwardly on opposite sides of the block. The lower ends of the bail are bent outwardly at right angles and are adapted to enter holes 35 in the inner face of the side walls 29. The cover is thus hinged to the bail. It may, therefore, be swung outwardly and upwardly to the position shown in chain lines in Figure 1, thereby exposing the terminal and conductor end for inspection or manipulation. It will be understood that the cover first moves outwardly from the block as the bail turns in the slot 33. When the bail has been swung through an angle of about 140, as shown, the cover is tilted back until it rests on the bushing [0. The slot 33 may be partially closed after the bail has been applied by crimping the edges with a suitable punch. This gives a frictional fit of the bail in the slot which sufiices to hold the bail in upright position until it is forced downwardly by manual pressure.

It will be apparent from the foregoing that the invention provides a simple yet effective terminal and cover for bushings such as those used for the high-voltage leads of distribution transformers. The construction is relatively inexpensive and requires but little machine work. The cover may conveniently be molded from suitable plastic. The principal advantage of the invention is that it permits the use of a straight bushing instead of the comparatively expensive curved-shank bushings employed heretofore. The downward and outward slope of the face of the block against which the conductor end is clamped permits the supply leads to be brought in at the same angle as employed with the curved-shank bushings. As a result, transformers having my improved terminal may be substituted for transformers constructed according to the prior practice without altering the position of the leads.

The cover protects linemen from accidental contact with the terminal and also serves as a guard to prevent short-circuiting of the transformer which might result, in the absence of the cover if a bird should alight on the terminal and come in contact with the transformer tank. The cover, furthermore, is secured to the terminal at all times and is not subject to being dropped aocidentally by the linemen when working on the terminal. At the same time, the cover may be tilted upwardly to an out-of-the-way position in an instant and as easily returned to its normal position enclosing the terminal and conductor end.

Although I have illustrated and described but a preferred embodiment of the invention, it will be recognized that changes in the details of construction disclosed may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim: 1

1. A bushing terminal comprising a block hav ing a face adapted to abut the end of a bushing, said block also having an exposed outer face and a stud normal thereto, said stud having a hole therethrough adapted to receive the end of a conductor, a bail swingably mounted on said block and depending therefrom on opposite sides thereof, and a hood-like cover open at the bottom and one end, said cover being hinged to the ends of the bail with the open end of the cover adjacent the end of the bushing, whereby the cover normally encloses the block and stud but may be swung upwardly and tilted to expose them. I

2. A bushing terminal as defined by claim 1 characterized by said block having a slot in the top thereof to receive said bail.

3. A bushing terminal as defined by claim 1' characterized by said exposed outer face of the block sloping downwardly and outwardly.

4. A bushing terminal as defined by claiml 4 abut the end of the bushing, means on said block adapted to receive a conductor end and secure it thereto, a bail swingably engaging said block and depending on both sides thereof, and a hoodlike cover open at the bottom and one end overlying said block with its open end adjacent the end of the bushing, said cover being hinged to the ends of said bail.

6. In a bushing terminal, a block adapted to abut the end of the bushing, means on said block adapted to receive a conductor end and secure it thereto, a slot in the top of said block, a bail seated in said slot with its ends depending on both sides of the block, and a hood-like cover open at the bottom and one end overlying said block with its open end adjacent the end of the bushing, said cover being hinged to the ends of the bail.

7. In a transformer or the like, a bushing, a terminal at the outer end of said bushing, means on said terminal adapted to receive a conductor end and secure it thereto, an insulating'hoodlike cover for said terminal and said end of said conductor, a connecting member pivoted to said terminal adjacent one end of said member and pivoted to said cover adjacent the other end of said member, the axes of said pivots being parallel and spaced, whereby said connecting member is adapted to permit the opening of said cover by the combined rotary and linear movement thereof relative to said bushing, and means on said terminal frictionally engaging said connecting means to hold said cover in open and closed position. p

8. In a transformer or the like, a bushing, a terminal at the outer end of said bushing, said terminal having means adapted to receive a conductor end and secure it to said terminal, a hoodlike cover for said terminal, said cover being open at the bottom and at one end thereof, a bail-like member swingably connecting said terminal and said cover to permit the opening and closing of said cover by a combined rotary and linear movement relative to said bushing, means on said ,ter-. minal frictionally engaging said bail-like member being adapted to hold said cover in open and.

closed position.

9. In a bushing terminal, a substantially horizontal bushing extending from the side of a transformer or the like, a terminal at the outer end of said bushing, said terminal having a face adapted for securing engagement with the end of a conductor extending downwardly and outwardly of said bushing, a hood-like cover open at the bottom and at one end thereof and adapted when in closed position to cover said terminal and said end of said conductor substantially from the outer end of said bushing outwardly thereof, a swingable member pivoted to said terminal adjacent its one end and pivoted to said-cover adjacent its other end, the axes of said pivots being parallel and spaced, said swingable member being adapted to permit the opening and closing of said cover by combined rotary and linear movement thereof relative to said bushing, means on said terminal frictionally engaging said swingable member for retaining said cover in open or closed position as desired, whereby said cover can be lifted entirely away from said terminal and moved rearwardly thereof while remaining so connected.

10. In a transformer or the like, a bushing including a terminal at its outer end, means on said terminal adapted to secure the end of a conductor, an insulating hood-like cover for said 5 terminal and said end of said conductor, a connecting member pivoted to said outer end adjacent one end of said member and pivoted to said cover adjacent the other end of said member, the axes of said pivots being parallel and spaced, means on said terminal frictionally engaging said connecting member to permit the opening of said cover by the combined rotary and linear movement thereof relative to said bushing in a plane normal to said axes, whereby said cover can be lifted entirely away from said said terminal and moved towards said bushing while remaining so connected.

JOHN J. ZIMSKY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 979,544 Murray Dec. 27, 1910 1,353,959 Holst Sept. 28, 1920 1,407,308 Vibber Feb. 21, 1922 2.409.042 Hermann Oct. 8. 1946 

